Project Tutorials

Chatter Finger Spinning Top

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I have two commercially made chatter tools,
a Sorby and a Stewart. Theyâre both designed similar in that the cutter
is a thin flat of cutting steel and it is held in a shaft so it can
be adjusted to extend or retract the blade.

Homemade versions made
from a piece of flat spring steel or even a butter knife blade will
work. Some turners produce their chatter by turning the stem thin
first and them presenting a tool to the wood to produce the chatter
patterns.

The Sorby chatter tool has two straight
blades that are ground to different profiles on each end. You get a
straight, pointed, concave and convex cutter profiles. The shaft is
beveled to angle the cutter down and has a ring and locking screw to
hold the blade in place. The Sorby blades are ground at 90 degrees.

The Dennis Stewart chatter tool has a blade
bent on the end to produce the downward angle of the blade. The blade
is held in a hole in the center of the shaft by a locking screw threaded
through the shaft itself. I think you can also buy a round profile
cutter from Stewart. I mainly use the pointed blade for all the chatter
I do. The blade of the Stewart tool has a bevel ground back to about
65 degrees.

Chatter works best on the endgrain of
real hard wood. I am using a piece of yellow heart because I will be
coloring the chatter later and need a light color wood to start with.
Other woods that chatter well are cocobolo, boxwood, ebony, lignum
vitea, and hard maple to name a few. The harder and denser the wood
the cleaner the chatter.

Chuck up a piece of suitable wood and start
to form the bottom of the top. Turn the bottom toward the tailstock
because the tip the top spins on is more important than the tip of
the stem, oriented this way allows free access to form the tip to
a good point.

A spindle gouge will do most all the cutting needed to
turn
a top.

The spindle gouge is oriented with the
bevel toward the wood left as our finished top surface. The cut itself
takes place just below the center of the gouge tip, the point nearest
the support of the tool rest. The cut starts above center on the spindle
and arcs down to the center point.

Take your time shaping the very tip. The
wood at the center is moving at a slower feet per minute speed so you
have to slow you tool advance to match.

The shape and surface finish from the gouge.
Keep developing the shape until you have what you want. The tip should
be slightly rounded, not a needle sharp point. The first time the top
drops on a hard floor the sharp point will break or deform and the
top will not spin well anymore.

The Sorby chatter tool in use. Raise the tool rest until
it is about center point high. The tip angled down so the top of the
blade can do the cutting. I have the lathe spinning at about 900 rpm's.
I start the chatter near the center and pivot the tip to the outer edge.
The cutting action is going to produce a loud squeal noise so be prepared.

Chatter patterns depend on several variables, lathe speed, density
of wood, sharpness of blade, rate of blade transverse across the surface,
pressure applied to wood, and length of blade extended from holder.
Spend
some time experimenting with all of the variations to achieve the
patterns you want.

The chatter pattern produced. If the pattern
does not look good to you, take the gouge and cut below the chatter
to give you a clean surface from which to start again with a different
lathe speed or other variable change.